Carbonyl Compounds

Question 1

what functional group do aldehydes and ketones contain?

Answer 1

Carbonyl functional group

Question 2

The part of the molecule which takes part in chemical reactions

Question 3

where is the carbonyl group in aldehydes?

Answer 3

they have the carbonyl group on a carbon with at least one hydrogen atoms attached to it

Question 4

where is the carbonyl group on a ketone?

Answer 4

attached to 2 alkyl groups

Question 5

What are primary alcohols oxidised to?

Answer 5

aldehydes

Question 6

what are secondary alcohols oxidised to?

Answer 6

ketones

Question 7

what do the oxidation reactions of secondary and primary alcohols produce?

Answer 7

water

Question 8

why can’t hydrochloric acid not be used with a powerful oxidising agent?

Answer 8

because the chloride ion could be oxidised

Question 9

what are phenols resistant to?

Answer 9

oxidation under normal conditions

Question 10

what can the aldehydes and ketones be reduced by and what is it normally done in?

Answer 10

Using sodium borohydride (NaBH4) normally this is done in aqueous solution or ethanol at room temperature

Question 11

what are the reduction products when aldehydes and ketones are reduced by sodium borohydride?

Answer 11

The corresponding alcohols

Question 12

what do aldehydes and ketones produce when they are reduced by sodium borohydride?

Answer 12

-Aldehydes produce primary alcohols
-Ketones produce secondary alcohols

Question 13

How can we show the reduction of ethanol?

Answer 13

using [H] as the reducing agent

Question 14

what is the carbonyl group in the aldehyde and ketone and what does this do?

Answer 14

polar which makes the carbon atom electron deficient and suspectible to attack by nucleophiles

Question 15

Why is the carbonyl group of an aldehyde and ketone unsaturated?

Answer 15

as it contains a carbon to oxygen double bond and it undergoes nucleophilic addition reaction to provide the one product; an alcohol.
The sodium borohydride generates the hydride (H) ion in solution.
sodium ion is a spectator and is never included in reaction mechanisms or equations.

Question 16

what does the reduction in the nucleophilic addition of hydride take place by?

Answer 16

the addition of the hydride ion across the carbonyl group followed by the protonation, by H+ or by water, of the intermediate organic species produced

Question 17

what does nucleophilic addition produce?

Answer 17

one product

Question 18

what does hydrogen cyanide produce and what can this do?

Answer 18

-the nucleophilic cyanide ion -CN, which can aso attack the carbonyl carbon of an aldehyde or ketone.
-The product is called a hydroxy nitrile (you may also see the name cyanohydrin).

Question 19

What can nitrites be reduced by and what does this produce?

Answer 19

using nickel and hydrogen to produce the corresponding amine

Question 20

What happens when a solution of 2,4-dinitrophenylhydrazine(Brady’s reagent) is added to an aldehyde or a ketone?

Answer 20

a deep yellow or orange solid is made

Question 21

What are aldehydes easily oxidised to and what by but what can ketones not do?

Answer 21

mild oxidising agents whereas ketones are cannot be oxidised further.

Question 22

what is Tollens’ reagent (ammoniacal silver nitrate)?

Answer 22

a weak oxidising agent, which can be used to distinguish between the aldehyde and the ketone.

Question 23

What happens when you add tollens’ reagent to an aldehyde and a ketone?

Answer 23

-Aldehyde- silver mirror is formed
-Ketone- No reaction

Question 24

what is the oxidising species in tollens’ reagent?

Answer 24

The aqueous silver (I) ions, Ag+ (aq)

Question 25

What happens when tollens’ reagent reacts with the aldehyde?

Answer 25

the aldehyde is oxidised to a carboxylic acid and the silver ions are reduced to silver metal

Question 26

is water produced when an aldehyde oxidised?

Answer 26

no